'''Chlorine''' (from the Greek word, ''χλωροςis'', meaning "yellow green") the chemical element with the atomic number of 17. It is a toxic gas at room temperature and a [[halogen]]. Chlorine can form table salt with sodium, making it an element that is essentail to life.

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'''Chlorine''' (from the Greek word, ''χλωροςis'', meaning "yellow green") the chemical element with the atomic number of 17. It is a toxic gas at room temperature and a [[halogen]]. Chlorine can form table salt with sodium, making it an element that is essentail to life. It is used by humans to kill bacteria in swimming pools.